Stirling cycle type engines are well known in the prior art. A Stirling cycle type engine operates on a regenerative thermodynamic cycle with cyclic compression and expansion of the working fluid at different temperature levels. The fluid flow is controlled by volume changes which create a net conversion of heat to work or vice versa. In a typical Stirling cycle type engine operating as a prime mover, heat is supplied to the working fluid at some high temperature when the fluid is in a hot chamber. Part of the heat is converted to work when, due to the absorbed heat, the working fluid expands and pushes on a piston, which is coupled to a crank shaft that imparts rotary motion. The working fluid is then displaced by a displacer through the hot chamber, through a regenerator where most of the heat is drawn off, and into a cold chamber, which is at some lower temperature. The piston then compresses the working fluid at the lower temperature. Next, the displacer pushes the working fluid through the cold chamber, through the regenerator, and into the hot chamber. As it passes through the regenerator the working fluid reabsorbs some of the heat previously deposited there. In the hot chamber the working fluid again absorbs heat and the cycle of operation repeats itself.
FIG. 1 is a schematic view of a prior art embodiment of a Stirling cycle type engine. This engine has four cylinders 1 which are annularly and equiangularly arranged, each having a displacer-piston 2 reciprocatingly disposed within it. Displacer-piston 2 divides the interior of cylinder 1 into two chambers: a hot or expansion chamber, and a cold or compression chamber. The hot chamber of one cylinder 1 and the cold chamber of an adjacent cylinder 1 are connected to each other through heater 3, regenerator 4 and cooler 5 which are serially connected. Each displacer-piston 2 is connected to incline plate 6 through connecting rod 7. This converts the reciprocating motion of the displacer-piston to rotating motion of output shaft 8.
In these Stirling cycle type engines four cylinders 1 are annularly and equiangularly arranged. This creates a large torque on output shaft 8 and hinders the smooth rotation of the shaft. Also, volumeric output of the engine is low. Thus, the Stirling cycle type engine of this type does not operate at high rotation speeds or high efficiency. Furthermore, the fastening structures for the heater and the cooler are very complicated. Also, the heat from the external heating source may be transferred to the cold chamber, causing heat conduction loss.